Automobiles and other vehicles provide a significant portion of transportation for commercial, government, and private entities. Vehicles, such as autonomous vehicles, drive on roadways that may have one or more bridges with different types of bridge surfaces. For example, some bridges have a metal roadway surface, such as a metal grate, on at least a portion of the bridge. The presence of a metal surface on the bridge presents a potential risk to the vehicle due to a loss of traction with the metal surface and a resulting loss of vehicle control. The metal surface, especially a metal grate, may cool faster than non-metal bridge surfaces and cause ice and snow to build-up on the metal grate sooner than surrounding roads and non-metal portions of the bridge. Thus, ice or snow on a metal surface presents a risk of injury to occupants of vehicles driving on the slippery metal surface. Detection of metal bridges can reduce the likelihood of accidents and potential injury to vehicle occupants.